This application requests a further 5 years of support for an Institutional National Research Service Award to support multi-disciplinary postdoctoral training in drug abuse (including nicotine and tobacco dependence) research. We request support for 6 post-doctoral fellows (MD and PhD) for primary training in one of 9 major areas: (i) systems neurobiology;(ii) molecular and cellular mechanisms;(iii) cognitive neuroscience;(iv) genetic methodology;(v) epidemiology;(vi) genetic epidemiology and behavioral genetic research;(vii) gene-mapping;(viii) molecular genetic research on substance use disorders and (ix) neurobiological and clinical aspects of pain and their treatment with opioid analgesics. In addition to specialization in a primary discipline, trainees will be encouraged to obtain a sufficient familiarity with at least one other focus area to facilitate cross-disciplinary collaborations in their research careers. The training program will ordinarily be of 3 years duration, reflecting the diverse background of our applicant pool (e.g. psychology, psychiatry, endocrinology, mathematics, economics, anthropology, sociology, neuroscience), or 2 years for those with pertinent research experience. Two year, and in special cases even one year, postdoctoral fellowships are also offered for experience drug abuse researchers seeking training in a new area of drug abuse research (e.g. human genetics). On average 2-3 new trainees will be recruited each year. The training program will emphasize a research apprenticeship model, combining research under the mentorship of one or more research mentors with more formal training through didactic courses or individualized tutorials. Major strengths of the program are: the availability of a large multi-disciplinary faculty with an active program of research on substance use disorders, representing expertise in many aspects of statistical/quantitative, molecular and genetic epidemiologic and neuroscience research on substance use disorders;a highly productive research environments (with preceptors having a total of 97 relevant funded research projects, career awards and science cores);the availability of major genetic epidemiological data-bases;access to a leading medical school, where trainees choose from a rich array of didactic courses, seminars and research experiences;and the long tradition at Washington University of successful mentoring and research training of scientists from diverse intellectual backgrounds for research on substance use disorders.